Cornthwaite embarked on the 1,004-mile journey on Aug. 10 in Chamberlain, S.D. He reached St. Louis 58 days later. He says he had to avoid obstacles in the water and risk hypothermia along the way.

Cornthwaite's swim was part of his effort to complete 25 thousand-mile journeys using non-motorized transport, to raise money for charities that raise awareness of breast cancer and support rural schools in Africa, Asia and Latin America. He has now completed seven journeys, including paddleboarding the Mississippi River and skateboarding across Australia.

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